U.S. patent application number 12/927275 was filed with the patent office on 2011-08-04 for pyrotechnic fin deployment and retention mechanism.
Invention is credited to John R. Sankovic.
Application Number | 20110186678 12/927275 |
Document ID | / |
Family ID | 44340774 |
Filed Date | 2011-08-04 |
United States Patent
Application |
20110186678 |
Kind Code |
A1 |
Sankovic; John R. |
August 4, 2011 |
Pyrotechnic fin deployment and retention mechanism
Abstract
A fin retention and deployment mechanism includes a detent in
each of a plurality of fins, a mechanism that engages the detent,
and at least one spring clip that maintains each of the fins in a
non-deployed position. The mechanism also includes a gas generator,
a manifold, coupled to the gas generator and having a plurality of
cylinders in fluid communication with gas from the gas generator,
and a plurality of pistons disposed in the cylinders. A bottom of
each of the pistons is coupled to each of the fins to provide
deployment thereof when a corresponding top of each of the pistons
is acted upon by gas from the gas generator. In response to the gas
generator expelling gas, the pistons may move the fins to a
deployed position.
Inventors: |
Sankovic; John R.;
(Chesterland, OH) |
Family ID: |
44340774 |
Appl. No.: |
12/927275 |
Filed: |
November 10, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12012998 |
Feb 7, 2008 |
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12927275 |
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Current U.S.
Class: |
244/3.27 |
Current CPC
Class: |
F42B 10/14 20130101;
F42B 10/20 20130101 |
Class at
Publication: |
244/3.27 |
International
Class: |
F42B 10/20 20060101
F42B010/20; F42B 10/14 20060101 F42B010/14 |
Goverment Interests
STATEMENT OF GOVERNMENT SUPPORT
[0001] This invention was made with U.S. government support under
Contract Number FA8681-06-C-0152. The U.S. government may have
certain rights in the invention.
Claims
1-8. (canceled)
9. A fin retention mechanism, comprising: a first detent in a fin;
a mechanism that engages the first detent; and at least one spring
clip that maintains the fin in a non-deployed position.
10. A fin retention mechanism, according to claim 9, further
comprising: a second detent that engages the mechanism.
11. A fin retention mechanism, according to claim 10, wherein the
fin is maintained in a non-deployed position in response to the
first detent engaging with the mechanism.
12. A fin retention mechanism, according to claim 11, wherein the
fin is maintained in a deployed position in response to the second
detent engaging with the mechanism and release of the fin from the
spring clip.
13. A fin retention mechanism, according to claim 9, wherein the
mechanism that engages the first detent includes a ball and a
spring that urges the ball toward the first detent.
14. A fin retention mechanism, according to claim 9, wherein the
mechanism that engages the first detent includes a plunger and a
spring that urges the plunger toward the first detent.
15-20. (canceled)
Description
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] This application relates to the field of fin deployment and
retention, and more particularly to the field of fin deployment and
retention for projectiles that are guided by fins.
[0004] 2. Description of Related Art
[0005] Projectiles that are guided by fins, such as bombs dropped
from aircraft, missiles, etc., may need to be stored in a
relatively compact manner prior to deployment. However, the fins on
the projectiles may limit the number of projectiles that may be
stored in a given space. In addition, storage and transport of
projectiles having fins may result in damage to the fins due to
movement that can be expected in the course of transportation.
[0006] One way to address these issues is to manually detach the
fins prior to deployment and then reattach the fins just prior to
use. However, this may be impractical for a number of reasons.
Manual reattachment may not be possible in situations when
projectiles are being stored and then deployed in an automated
fashion. For example, it may be desirable to store the projectiles
in an aircraft bomb compartment that is opened while the aircraft
is in flight.
[0007] As an alternative to manual fin deployment, the fins may be
folded close to the body of the projectile for storage and
transport and then automatically deployed just prior to use.
However, for such a system, it is important that all of the fins be
reliably deployed for the projectile to operate properly. In
addition, it is also useful to avoid premature deployment (e.g.,
from jostling the aircraft) since premature deployment may cause
the fins to be damaged and/or adversely affect deployment of the
projectiles altogether.
[0008] Accordingly, it is desirable to provide a system that
addresses the needs set forth above.
SUMMARY OF THE INVENTION
[0009] According to the system described herein, a fin deployment
mechanism includes a gas generator, a manifold, coupled to the gas
generator and having a plurality of cylinders in fluid
communication with gas from the gas generator, and a plurality of
pistons disposed in the cylinders, a bottom of each of the pistons
being coupled to a fin to provide deployment thereof when a
corresponding top of each of the pistons is acted upon by gas from
the gas generator. The fin deployment mechanism may also include a
valve coupled to the gas generator to control a flow of gas
therefrom. The gas generator may be implemented using a chemical
initiator. The fin deployment mechanism may also include a
plurality of springs, disposed in the cylinders, to bias the
pistons away from the fins. The pistons may be directly coupled to
the fins or may be coupled to the fins through a padding element.
The padding element may be made from a material that is softer than
a material used for the fins. The fins may be made from 7075-T6
aluminum while the padding element 68 may be made from 6061-T6
aluminum.
[0010] According further to the system described herein, a fin
retention mechanism includes a first detent in a fin, a mechanism
that engages the first detent, and at least one spring clip that
maintains the fin in a non-deployed position. The fin retention
mechanism may also include a second detent that engages the
mechanism. The fin may be maintained in a non-deployed position in
response to the first detent engaging with the mechanism. The fin
may be maintained in a deployed position in response to the second
detent engaging with the mechanism and release of the fin from the
spring clip. The mechanism that engages the first detent may
include a ball and a spring that urges the ball toward the first
detent. The mechanism that engages the first detent may include a
plunger and a spring that urges the plunger toward the first
detent.
[0011] According further to the system described herein, a fin
retention and deployment mechanism includes a first detent in each
of a plurality of fins, a mechanism that engages the first detent,
at least one spring clip that maintains each of the fins in a
non-deployed position, a gas generator, a manifold, coupled to the
gas generator and having a plurality of cylinders in fluid
communication with gas from the gas generator, and a plurality of
pistons disposed in the cylinders, a bottom of each of the pistons
being coupled to each of the fins to provide deployment thereof
when a corresponding top of each of the pistons is acted upon by
gas from the gas generator. The fin retention and deployment
mechanism may also include a plurality of springs, disposed in the
cylinders, to bias the pistons away from the fins. The pistons may
be coupled to the fins through a padding element that is made from
a material that is softer than a material used for the fins. In
response to the gas generator expelling gas, the pistons may move
the fins to a deployed position and a second detent in each of the
fins may engage the mechanism to maintain the fins in a deployed
position. The mechanism that engages the detents may include a ball
and a spring that urges the ball toward the detents and/or may
include a plunger and a spring that urges the plunger toward the
detents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Embodiments of the system are described with reference to
the several figures of the drawings, in which:
[0013] FIG. 1 is a schematic diagram of a fin assembly in which the
fins are in a non-deployed position according to an embodiment of
the system described herein.
[0014] FIG. 2 is a schematic diagram of a fin assembly in which the
fins are in a deployed position according to an embodiment of the
system described herein.
[0015] FIG. 3 is a schematic diagram showing a fin retention
mechanism according to an embodiment of the system described
herein.
[0016] FIG. 4 is a schematic diagram illustrating a fin deployment
mechanism according to an embodiment of the system described
herein.
[0017] FIG. 5A is a schematic diagram illustrating in more detail a
fin deployment mechanism according to an embodiment of the system
described herein.
[0018] FIG. 5B is a schematic diagram illustrating in more detail
an alternative fin deployment mechanism according to an embodiment
of the system described herein.
[0019] FIG. 6 is a schematic diagram illustrating a manifold of a
gas deployment mechanism according to an embodiment of the system
described herein.
[0020] FIG. 7 is a schematic diagram illustrating additional fin
retention mechanisms according to an embodiment of the system
described herein.
[0021] FIG. 8 is a schematic diagram illustrating a spring clip
used for fin retention according to an embodiment of the system
described herein.
[0022] FIG. 9 is a schematic diagram illustrating a plunger used
for fin retention according to an embodiment of the system
described herein.
DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS
[0023] Referring now to the figures of the drawings, the figures
comprise a part of this specification and illustrate exemplary
embodiments of the described system. It is to be understood that in
some instances various aspects of the system may be shown
schematically or may be exaggerated or altered to facilitate an
understanding of the system.
[0024] Referring to FIG. 1, a control actuated fin assembly 20 is
shown as including a base 22, a plurality of fins 26a, 26b, and a
plurality of fin holders 28a, 28b. The fins 26a, 26b are shown in
FIG. 1 in a folded, non-deployed, position. The system described
herein allows for the fins 26a, 26b to be maintained in the
non-deployed position to facilitate storage and/or transportation.
The base 22 may represent a portion of a missile, a rocket, a
torpedo, a flying drone, or similar device (projectile) that uses
fins for navigation. Note that, although only the two fins 26a, 26b
and the corresponding fin holders 28a, 28b are shown in FIG. 1, any
number may be used. In an embodiment herein, the base 22 includes
four fins, the two fins 26a, 26b shown in FIG. 1 and two additional
fins not shown in 1 that are perpendicular to the view of FIG. 1.
For the discussion herein, it should be assumed that, unless
otherwise stated, reference to the two shown fins 26a, 26b include
reference to all the fins being used.
[0025] The fin holders 28a, 28b include pins 32a, 32b that retain
the fins 26a, 26b to the body 22. The pin 32a retains the fin 26a
while the pin 32b retains the fin 26b. As described in more detail
elsewhere herein, each of the fins 26a, 26b rotates about a
corresponding one of the pins 32a, 32b to move the fins 26a, 26b
into a deployed position. The base 22 also includes electronics 34
that are used in connection with deployment of the fins 26a, 26b
and/or possibly actuation of the fins 26a, 26b for navigation of
the projectile. The electronics 34 may receive one or more signals
(e.g., transmitted radio frequency electronic signals, signals from
a coupled tether, etc.) and may cause deployment of the fins 26a,
26b by providing one or more signals to electromechanical devices
(not shown in FIG. 1), as described in more detail elsewhere
herein.
[0026] Referring to FIG. 2, the assembly 20 is shown with the fins
26a, 26b deployed. As described in more detail elsewhere herein, an
appropriate mechanism may be used to retain the fins 26a, 26b in a
deployed position. In some embodiments, the mechanism may be
provided in the fin holders 28a, 28b. In addition, in some
embodiments, the mechanism that retains the fins 26a, 26b in a
deployed position as shown in FIG. 2 may share at least some
components with a mechanism that retains the fins 26a, 26b in a
non-deployed position as shown in FIG. 1. In some embodiments, once
the fins 26a, 26b are deployed, the fins 26a, 26b may be actuated
(tilted) in a conventional manner using, for example, the
electronics 34 and/or other electronic flight controls coupled to
one or more electro-mechanical servos (not shown) that move the
fins 26a, 26b.
[0027] Referring to FIG. 3, the fin 26b and the corresponding fin
holder 28b are shown in more detail to illustrate a mechanism for
retaining the fins 26a, 26b in a non-deployed position as shown in
FIG. 1 and for maintaining the fins 26a, 26b in a deployed position
as shown in FIG. 2. The fin 26b is shown as including a first
detent 42 that accepts a ball 44 that is urged into the detent 42
by a spring 46. The ball 44 and the spring 46 may act as a
retaining mechanism to retain the fin 26b in a deployed
position.
[0028] The ball 44 and the spring 46 may be provided in a shaft 48
that is part of the fin holder 28b. In other embodiments, at least
part of the shaft 48 may be part of the base 22. The shaft 48 may
be cylindrical, although other shapes may also be used, including,
without limitation, a shaft having a square, rectangular, oval,
etc. cross section. In addition, instead of the ball 44, it may be
possible to use other appropriate mechanisms, including using a
plunger, as described in more detail elsewhere herein.
[0029] The fin 26b may also include a second detent 52 that engages
the retaining mechanism formed by the ball 44 and the spring 46
when the fin 26b is in a non-deployed position as shown in FIG. 1.
Just as with the deployed position, the spring 46 urges the ball 44
into the detent 52 to retain the fin 26b in a non-deployed
position. Note also that other appropriate retaining mechanisms may
be used in place of the ball 44 and the spring 46. Furthermore, as
described in more detail elsewhere herein, additional retaining
mechanisms may be used in conjunction with the mechanism that
engages the detent 52.
[0030] Referring to FIG. 4, the fin 26b is shown in a non-deployed
position. The body 22 contains a deployment mechanism 62 having a
gas generator 64 and a manifold 66. As described in more detail
elsewhere herein, the manifold 66 has a separate outlet for each
fin and each outlet is in fluid communication with the gas
generator 64. As set forth below, each outlet may contain a piston
that is acted upon by the gas from the generator 64 to push on and
deploy all of the fins substantially simultaneously. The deployment
mechanism 62 may be attached to the body 22 using any appropriate
mechanism, including being bolted to the body through bolt holes
(not shown) provided in the deployment mechanism 62.
[0031] In an embodiment herein, a padding element 68 is provided to
cushion the force of the piston to prevent the piston from damaging
the fin 26b. The padding element 68 may be made from a material
that is somewhat softer than the material used for making the fin
26b. For example, the fin 26b (and all the other fins) may be made
from 7075-T6 aluminum while the padding element 68 may be made from
a somewhat softer 6061-T6 aluminum. Of course, other appropriate
materials may be used for either the fins 26a, 26b and/or the
padding element 68. Note that if the padding element 68 is too
hard, the fins 26a, 26b may be damaged during deployment while if
the padding element 68 is too soft, the padding element 68 may
deform without the fins 26a, 26b being properly deployed.
[0032] Referring to FIG. 5A, the deployment mechanism 62 is shown
in more detail as including a plurality of cylinders 72a, 72b in
fluid communication with the gas generator 64. Gas from the gas
generator 64 may be released into the cylinders 72a, 72b in a rapid
manner using an appropriate valve 74 that may be controlled
externally by, for example, the electronics 34 shown in FIG. 1 and
FIG. 2. Thus, all of the fins 26a, 26b may be deployed
simultaneously by actuating the valve 74.
[0033] In an embodiment herein, the valve 74 may be actuated by the
electronics 34 and/or by some other appropriate mechanism. Note
that the electronics 34 may also separately handle actuation of the
fins 26a, 26b for navigation. In other embodiments, a sensor may be
used to detect when the system is being deployed (e.g., released
from an aircraft in flight) and/or an external signal may be
provided to indicate when the system is being deployed. In some
embodiments, actuation of the valve 74 is sufficient to deploy the
fins 26a, 26b. Note that the valve 74 may be implemented using a
squib that is configured so that detonation of the squib causes the
gas in the gas generator 64 to be rapidly released.
[0034] The cylinder 72a includes a piston 76a while the cylinder
72b includes a piston 76b. A top of each of the pistons 76a, 76b is
acted upon by the gas from the gas generator 64 so that the bottom
of each of the pistons 76a, 76b extends outward from the manifold
66 to deploy the fins 26a, 26b. In some embodiments, the bottoms of
the pistons 76a, 76b may be coupled directly to the fins 26a, 26b.
In other embodiments, the bottoms of the pistons 76a, 76b may be
coupled to the fins 26a, 26b indirectly through the padding element
68, discussed above.
[0035] In an embodiment herein, the piston 76a may be provided with
a spring 78a and the piston 76b may be provided with a spring 78b.
The springs 78a, 78b may bias the pistons 76a, 76b in a direction
opposite to the direction the pistons are pushed by gas from the
gas generator 64. The springs 78a, 78b may facilitate providing an
appropriate force to deploy the fins 26a, 26b and, in addition, may
facilitate assembly of the system by retaining the pistons 76a, 76b
within the manifold 66 during assembly.
[0036] Referring to FIG. 5B, an alternative deployment mechanism
62' is shown in detail as including the cylinders 72a, 72b in fluid
communication with an alternative gas generator 64'. Just as with
the deployment mechanism 62 of FIG. 5A, gas from the gas generator
64' may be released into the cylinders 72a, 72b in a rapid manner
to deploy all of the fins 26a, 26b simultaneously. However, the
alternative gas generator 64' may be implemented using a chemical
initiator, such as that provided by Special Devices, Inc. of
Newhall, Calif. under part no. 103377. The alternative gas
generator 64' includes a reactive powder 65 that rapidly releases a
significant amount of gas when ignited. The powder 65 may be
ignited using an electrical resistive element/squib 79 that is
coupled to and actuated by the electronics 34. Operation of the
pistons 76a, 76b and springs 78a, 78b may be like that of the
deployment mechanism 62 of FIG. 5A, described above.
[0037] Referring to FIG. 6, the manifold 66 is shown from a top
view as including additional cylinders 72c, 72d, additional pistons
76c, 76d, and additional springs 78c, 78d which operate in a manner
similar to that discussed above in connection with the cylinders
72a, 72b, pistons 76a, 76b, and springs 78a, 78b. In an embodiment
herein, there are four fins that are deployed although, as
discussed elsewhere herein, any number of fins may be used. All of
the cylinders 72a-72d are in fluid communication with the gas
generator 64 (not shown in FIG. 6). Thus, sufficient gas pressure
causes the pistons 76a-76d to traverse the respective ones of the
cylinders 72a-72d to deploy the corresponding fins more or less
simultaneously.
[0038] Note that if the size (pressure) provided by the gas
generator 64 (or the gas generator 64' or any other gas generator
that is used) is too small, the fins 26a, 26b may not reliably
deploy. On the other hand, if the size is too large, the fins 26a,
26b (and/or other components) may become damaged in connection with
deployment. Accordingly, it may be desirable to determine a minimal
size (pressure) for the gas generator and then choose a size that
is a nominal percentage above the minimal size.
[0039] The amount of pressure, Pd, needed on the pistons 76a-76d to
deploy the fins 26a, 26b, may be determined empirically. Similarly,
the volume of the gas generator (e.g., the gas generator 64 or the
gas generator 64'), the manifold 66, and the cylinders 72a-72d may
also be determined. If V1 is the sum of the volumes of the gas
generator, the manifold 66, and the cylinders 72a, 72d, and V2 is a
reference volume used to test/spec the gas generator, then the
following may be used to determine a minimum amount of pressure,
Pg, for the gas generator at the reference volume V2:
Pg=(Pd*V2)/V1
For example, if it is determined that 4800 p.s.i. are needed to
deploy the fins 26a, 26b, and if V1 is 2.5 CC and V2 is 10 CC, then
the minimum pressure needed for the gas generator at the reference
volume is 1200 p.s.i. This minimum may be then adjusted (increased)
to account for expected variances in tolerance that could require
more than 4800 p.s.i. to deploy the fins 26a, 26b and/or variances
in actual values for V1 and V2. For example, 10% may be added to
the calculated minimum pressure to provide an operating pressure of
1320 p.s.i. for the gas generator. The reference volume may be a
volume used by the manufacturer/reseller to specify the capacity of
the gas generator (e.g., delivers 1200 p.s.i. at 10 CC).
[0040] Note that the operating pressure for the gas generator
should be present at a minimum operating temperature of the system
(e.g., -65.degree. F.) and that the equation above may be used to
determine the maximum pressure on the pistons 76a-76d at a maximum
operating temperature (e.g., +160.degree. F.). In instances where
the pressure on the pistons 76a-76d is determined to be too high at
the maximum operating temperature, the system may be adjusted by,
for example, changing the volume of the gas generator and then
determining a new operating pressure for the gas generator.
[0041] Referring to FIG. 7, the fin 26b is shown in a non-deployed
position as being retained by a second retaining mechanism that
includes a spring clip 82 and a third retaining mechanism that
includes a ball 84 and a detent 86 in the fin 26b, The ball 84 and
the detent 86 may be like the ball 44 and the detent 42 discussed
above. The spring clip 82 may be a metal deformable clip, as
discussed in more detail elsewhere herein.
[0042] Referring to FIG. 8, the spring clip 82 is shown in more
detail in profile. The spring clip 82 exerts a force in a direction
indicated by the arrows in FIG. 8 to retain an edge of the fin 26b
that is shaped to be gripped by the spring clip 82. The spring clip
82 may retain the fin 26b in a non-deployed position until
sufficient force is generated (e.g., by the deployment mechanism
62, discussed above) to pull the fin 26b away from the spring clip
82.
[0043] Referring to FIG. 9, an alternative implementation of the
retaining mechanism of FIG. 3 is shown with the shaft 46 and the
spring 48. However, instead of the ball 44 of FIG. 3, FIG. 9 shows
a plunger 94 having a rounded end. The plunger 94 may be used
instead of the ball 44 and/or instead of the ball 84 of FIG. 7.
Note also that any or all of the retaining mechanisms illustrated
herein may be used in any combination and/or eliminated so that,
for example, it is possible to use only the retaining mechanism of
FIG. 3, use the retaining mechanism of FIG. 3 in combination with
the spring clip 82, use all of the retaining mechanisms described
herein, etc.
[0044] Other embodiments of the invention will be apparent to those
skilled in the art from a consideration of the specification or
practice of the invention disclosed herein. It is intended that the
specification and examples be considered as exemplary only, with
the true scope and spirit of the invention being indicated by the
following claims.
* * * * *